The invention relates to a pellet implant gun especially suitable for use in implanting growth, anabolic or other medicinal pellets under the skin of domestic animals. Use of subcutaneously implanted growth materials is now a common practice in cattle and lamb feedlots, particularly since the feeding of diethyl stilbesterol is a controversial procedure. These growth stimulants are provided by the pharmaceutical manufacturer in pellet form, and for ease in handling and use are commonly packaged with a number of the pellets in a single plastic cartridge. There are known a number of devices, commonly referred to as "implant guns", for implanting these pellets. All of these guns utilize a hollow needle of relatively large diameter which is inserted subcutaneously into the selected implant site of the animal, usually the ear. The prior art implant guns, however, commonly utilize a ram that pushes the pellets out of the cartridge which has been positioned inside of the hollow needle. If enough force is utilized to force the pellets from the end of the needle and into the tissue at the implant site, they often will break. If this occurs, the implanting sometimes must be repeated since all of the pellets will not be inserted under the skin of the animal. Also, if a pellet breaks after it is inserted under the skin, it will be absorbed into the animal's system at a rate that is not desirable and which can sometimes cause adverse side effects on the animal. There is, therefore, a need for an implant gun that will eliminate or greatly minimize the possibility of the pellets being broken at the time they are inserted at the implant site.
Also, there is being developed a variety of means for identifying animals in a manner other than the traditional branding. In large feedlots, it may be desirable for different purposes to place identifying marks on the animals. With the large number of animals in some of the feedlots, checking the identification of the animals can be a very time-consuming process. Therefore, animals are sometimes tagged with special tags which can be detected by means other than visually. It is possible that future developments may permit the implanting of identification means that can be detected electronically so that massive identification of animals can be conducted very rapidly. There is, therefore, a developing need for an implant gun that can also implant metal identification tags for this purpose.
Although the technology has not yet advanced to the point where mass implanting of medicinal pellets in humans is practical, the future use of implant materials in human medicine for birth control, allergy treatment, long-term inoculation, etc. is not inconceivable. Therefore, a need could develop for a suitable implant gun for use in human medicine. If developed for use in human medicine, an implant gun would have to be one which would use as small a needle as possible, handle fragile pellets, and be capable of use with a minimum of trauma to the patient.